perf: Convert perf_event to local_t

Since now all modification to event->count (and ->prev_count
and ->period_left) are local to a cpu, change then to local64_t so we
avoid the LOCK'ed ops.

Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
LKML-Reference: <new-submission>
Signed-off-by: Ingo Molnar <mingo@elte.hu>

1 files changed, 9 insertions, 9 deletions

diff --git a/arch/arm/kernel/perf_event.c b/arch/arm/kernel/perf_event.c
index c45768614c8a..5b7cfafc0720 100644
--- a/arch/arm/kernel/perf_event.c
+++ b/arch/arm/kernel/perf_event.c
@@ -164,20 +164,20 @@ armpmu_event_set_period(struct perf_event *event,
                         struct hw_perf_event *hwc,
                         int idx)
 {
-        s64 left = atomic64_read(&hwc->period_left);
+        s64 left = local64_read(&hwc->period_left);
         s64 period = hwc->sample_period;
         int ret = 0;
 
         if (unlikely(left <= -period)) {
                 left = period;
-                atomic64_set(&hwc->period_left, left);
+                local64_set(&hwc->period_left, left);
                 hwc->last_period = period;
                 ret = 1;
         }
 
         if (unlikely(left <= 0)) {
                 left += period;
-                atomic64_set(&hwc->period_left, left);
+                local64_set(&hwc->period_left, left);
                 hwc->last_period = period;
                 ret = 1;
         }
@@ -185,7 +185,7 @@ armpmu_event_set_period(struct perf_event *event,
         if (left > (s64)armpmu->max_period)
                 left = armpmu->max_period;
 
-        atomic64_set(&hwc->prev_count, (u64)-left);
+        local64_set(&hwc->prev_count, (u64)-left);
 
         armpmu->write_counter(idx, (u64)(-left) & 0xffffffff);
 
@@ -204,18 +204,18 @@ armpmu_event_update(struct perf_event *event,
         s64 delta;
 
 again:
-        prev_raw_count = atomic64_read(&hwc->prev_count);
+        prev_raw_count = local64_read(&hwc->prev_count);
         new_raw_count = armpmu->read_counter(idx);
 
-        if (atomic64_cmpxchg(&hwc->prev_count, prev_raw_count,
+        if (local64_cmpxchg(&hwc->prev_count, prev_raw_count,
                              new_raw_count) != prev_raw_count)
                 goto again;
 
         delta = (new_raw_count << shift) - (prev_raw_count << shift);
         delta >>= shift;
 
-        atomic64_add(delta, &event->count);
-        atomic64_sub(delta, &hwc->period_left);
+        local64_add(delta, &event->count);
+        local64_sub(delta, &hwc->period_left);
 
         return new_raw_count;
 }
@@ -478,7 +478,7 @@ __hw_perf_event_init(struct perf_event *event)
         if (!hwc->sample_period) {
                 hwc->sample_period  = armpmu->max_period;
                 hwc->last_period    = hwc->sample_period;
-                atomic64_set(&hwc->period_left, hwc->sample_period);
+                local64_set(&hwc->period_left, hwc->sample_period);
         }
 
         err = 0;